esp-idf/components/wpa_supplicant/src/crypto/sha256.c
kapil.gupta ad7cb5f5c1 wpa_supplicant: Write Crypto API based on mbedtls
This commit add following crypto changes

1. Update current crypto code with upstream supplicant code
2. Add a proper porting layer to use mbedtls APIs for all the crypto
   operations used by supplicant.

Internal crypto will be used when USE_MBEDLTS flag is disabled
in supplicant's menuconfig.

This commit also removes the clutter in crypto files due to partial
porting of some APIs to mbedtls, all the code from those files have
been removed and rewritten in a generic way, this is inspired from
current upstream code.

This also reduces the lib size significantly, supplicant's lib
size reduces around ~567kb after this change(NB: lib size doesn't
indicate reduction in final bin size).
2021-05-04 10:54:57 +00:00

105 lines
2.6 KiB
C

/*
* SHA-256 hash implementation and interface functions
* Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "sha256.h"
#include "crypto.h"
/**
* hmac_sha256_vector - HMAC-SHA256 over data vector (RFC 2104)
* @key: Key for HMAC operations
* @key_len: Length of the key in bytes
* @num_elem: Number of elements in the data vector
* @addr: Pointers to the data areas
* @len: Lengths of the data blocks
* @mac: Buffer for the hash (32 bytes)
* Returns: 0 on success, -1 on failure
*/
int hmac_sha256_vector(const u8 *key, size_t key_len, size_t num_elem,
const u8 *addr[], const size_t *len, u8 *mac)
{
unsigned char k_pad[64]; /* padding - key XORd with ipad/opad */
unsigned char tk[32];
const u8 *_addr[11];
size_t _len[11], i;
if (num_elem > 10) {
/*
* Fixed limit on the number of fragments to avoid having to
* allocate memory (which could fail).
*/
return -1;
}
/* if key is longer than 64 bytes reset it to key = SHA256(key) */
if (key_len > 64) {
if (sha256_vector(1, &key, &key_len, tk) < 0)
return -1;
key = tk;
key_len = 32;
}
/* the HMAC_SHA256 transform looks like:
*
* SHA256(K XOR opad, SHA256(K XOR ipad, text))
*
* where K is an n byte key
* ipad is the byte 0x36 repeated 64 times
* opad is the byte 0x5c repeated 64 times
* and text is the data being protected */
/* start out by storing key in ipad */
os_memset(k_pad, 0, sizeof(k_pad));
os_memcpy(k_pad, key, key_len);
/* XOR key with ipad values */
for (i = 0; i < 64; i++)
k_pad[i] ^= 0x36;
/* perform inner SHA256 */
_addr[0] = k_pad;
_len[0] = 64;
for (i = 0; i < num_elem; i++) {
_addr[i + 1] = addr[i];
_len[i + 1] = len[i];
}
if (sha256_vector(1 + num_elem, _addr, _len, mac) < 0)
return -1;
os_memset(k_pad, 0, sizeof(k_pad));
os_memcpy(k_pad, key, key_len);
/* XOR key with opad values */
for (i = 0; i < 64; i++)
k_pad[i] ^= 0x5c;
/* perform outer SHA256 */
_addr[0] = k_pad;
_len[0] = 64;
_addr[1] = mac;
_len[1] = SHA256_MAC_LEN;
return sha256_vector(2, _addr, _len, mac);
}
/**
* hmac_sha256 - HMAC-SHA256 over data buffer (RFC 2104)
* @key: Key for HMAC operations
* @key_len: Length of the key in bytes
* @data: Pointers to the data area
* @data_len: Length of the data area
* @mac: Buffer for the hash (32 bytes)
* Returns: 0 on success, -1 on failure
*/
int hmac_sha256(const u8 *key, size_t key_len, const u8 *data,
size_t data_len, u8 *mac)
{
return hmac_sha256_vector(key, key_len, 1, &data, &data_len, mac);
}